<?php
	/**************************************************************************\
	* eGroupWare - eGroupWare Interapplication Links                           *
	* http://www.egroupware.org                                                *
	* Written by Ralf Becker <RalfBecker@outdoor-training.de>                  *
	* --------------------------------------------                             *
	*  This program is free software; you can redistribute it and/or modify it *
	*  under the terms of the GNU General Public License as published by the   *
	*  Free Software Foundation; either version 2 of the License, or (at your  *
	*  option) any later version.                                              *
	\**************************************************************************/

	/* $Id$ */

	include_once(EGW_API_INC . '/class.solink.inc.php');
	
	/**
	 * generalized linking between entries of eGroupware apps - BO layer
	 *
	 * Links have two ends each pointing to an entry, each entry is a double:
	 * 	 - app   app-name or directory-name of an egw application, eg. 'infolog'
	 * 	 - id    this is the id, eg. an integer or a tupple like '0:INBOX:1234'
	 *
	 * The BO-layer implementes 2 extra features on top of the so-layer:
	 * 1) It handles links to not already existing entries. This is used by the eTemplate link-widget, which allows to
	 *    setup links even for new / not already existing entries, before they get saved.
	 * 	  In that case you have to set the first id to 0 for the link-function and pass the array returned in that id 
	 * 	  (not the return-value) after saveing your new entry again to the link function.
	 * 2) Attaching files: they are saved in the vfs and not the link-table (!).
	 *    Attached files are stored under $vfs_basedir='/infolog' in the vfs!
	 *
	 * @package api
	 * @subpackage link
	 * @author Ralf Becker <RalfBecker@outdoor-training.de>
	 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
	 */
	class bolink extends solink
	{
		/**
		 * other apps can participate in the linking by implementing a 'search_link' hook, which
		 * has to return an array in the format of an app_register entry below
		 * @var array $app_register
		 */
		var $app_register = array(
			'addressbook' => array(
				'query' => 'addressbook_query',
				'title' => 'addressbook_title',
				'view' => array(
					'menuaction' => 'addressbook.uicontacts.view'
				),
				'view_id' => 'contact_id',
				//'view_popup' => '800x600',
			),
			'projects' => array(
				'query' => 'projects_query',
				'title' => 'projects_title',
				'view' => array (
					'menuaction' => 'projects.uiprojects.view_project'
				),
				'view_id' => 'project_id'
			),
/*
			'email' => array(
				'view' => array(
					'menuaction' => 'email.uimessage.message'
				),
				'view_id' => 'msgball[acctnum:folder:msgnum]'	// id is a tupple/array, fields separated by ':'
			),
 */
		);
		var $public_functions = array(	// functions callable via menuaction
			'get_file' => True
		);
		var $vfs;
		var $vfs_basedir='/infolog';
		var $vfs_appname='file';		// pseudo-appname for own file-attachments in vfs, this is NOT the vfs-app
		var $valid_pathes = array();
		var $send_file_ips = array();

		/**
		 * constructor
		 */
		function bolink( )
		{
			$this->solink( );					// call constructor of derived class

			$this->vfs =& CreateObject('phpgwapi.vfs');

			$this->link_pathes   = $GLOBALS['egw_info']['server']['link_pathes'];
			$this->send_file_ips = $GLOBALS['egw_info']['server']['send_file_ips'];
			
			// other apps can participate in the linking by implementing a search_link hook, which
			// has to return an array in the format of an app_register entry
			// for performance reasons, we do it only once / cache it in the session
			if (!($search_link_hooks = $GLOBALS['egw']->session->appsession('search_link_hooks','phpgwapi')))
			{
				$search_link_hooks = $GLOBALS['egw']->hooks->process('search_link');
				$GLOBALS['egw']->session->appsession('search_link_hooks','phpgwapi',$search_link_hooks);
			}
			if (is_array($search_link_hooks))
			{
				foreach($search_link_hooks as $app => $data)
				{
					if (is_array($data))
					{
						$this->app_register[$app] = $data;
					}
				}
			}
		}
		
		/**
		 * creats a link between $app1,$id1 and $app2,$id2 - $id1 does NOT need to exist yet
		 *
		 * Does NOT check if link already exists.
		 * File-attachments return a negative link-id !!!
		 *
		 * @param string $app1 app of $id1
		 * @param string/array &$id1 id of item to linkto or 0 if item not yet created or array with links 
		 * 	of not created item or $file-array if $app1 == $this->vfs_appname (see below).
		 * 	If $id==0 it will be set on return to an array with the links for the new item.
		 * @param string/array $app2 app of 2.linkend or array with links ($id2 not used)
		 * @param string $id2='' id of 2. item of $file-array if $app2 == $this->vfs_appname (see below)<br>
		 * 	$file array with informations about the file in format of the etemplate file-type<br>
		 * 	$file['name'] name of the file (no directory)<br>
		 * 	$file['type'] mine-type of the file<br>
		 * 	$file['tmp_name'] name of the uploaded file (incl. directory)<br>
		 * 	$file['path'] path of the file on the client computer<br>
		 * 	$file['ip'] of the client (path and ip in $file are only needed if u want a symlink (if possible))
		 * @param string $remark='' Remark to be saved with the link (defaults to '')
		 * @param int $owner=0 Owner of the link (defaults to user)
		 * @param int $lastmod=0 timestamp of last modification (defaults to now=time())
		 * @param int $no_notify=0 &1 dont notify $app1, &2 dont notify $app2
		 * @return int/boolean False (for db or param-error) or on success link_id (Please not the return-value of $id1)
		 */
		function link( $app1,&$id1,$app2,$id2='',$remark='',$owner=0,$lastmod=0,$no_notify=0 )
		{
			if ($this->debug)
			{
				echo "<p>bolink.link('$app1',$id1,'".print_r($app2,true)."',".print_r($id2,true).",'$remark',$owner,$lastmod)</p>\n";
			}
			if (!$app1 || !$app2 || $app1 == $app2 && $id1 == $id2)
			{
				return False;
			}
			if (is_array($id1) || !$id1)		// create link only in $id1 array
			{
				if (!is_array($id1))
				{
					$id1 = array( );
				}
				$link_id = $this->temp_link_id($app2,$id2);

				$id1[$link_id] = array(
					'app' => $app2,
					'id'  => $id2,
					'remark' => $remark,
					'owner'  => $owner,
					'link_id' => $link_id,
					'lastmod' => time()
				);
				if ($this->debug)
				{
					_debug_array($id1);
				}
				return $link_id;
			}
			if (is_array($app2) && !$id2)
			{
				reset($app2);
				$link_id = True;
				while ($link_id && list(,$link) = each($app2))
				{
					if (!is_array($link))	// check for unlink-marker
					{
						//echo "<b>link='$link' is no array</b><br>\n";
						continue;
					}
					if ($link['app'] == $this->vfs_appname)
					{
						$link_id = $this->attach_file($app1,$id1,$link['id'],$link['remark']);
					}
					else
					{
						$link_id = solink::link($app1,$id1,$link['app'],$link['id'],
							$link['remark'],$link['owner'],$link['lastmod']);
						
						// notify both sides
						if (!($no_notify&2)) $this->notify('link',$link['app'],$link['id'],$app1,$id1,$link_id);
						if (!($no_notify&1)) $this->notify('link',$app1,$id1,$link['app'],$link['id'],$link_id);
					}
				}
				return $link_id;
			}
			if ($app1 == $this->vfs_appname)
			{
				return $this->attach_file($app2,$id2,$id1,$remark);
			}
			elseif ($app2 == $this->vfs_appname)
			{
				return $this->attach_file($app1,$id1,$id2,$remark);
			}
			$link_id = solink::link($app1,$id1,$app2,$id2,$remark,$owner);

			if (!($no_notify&2)) $this->notify('link',$app2,$id2,$app1,$id1,$link_id);
			if (!($no_notify&1)) $this->notify('link',$app1,$id1,$app2,$id2,$link_id);
			
			return $link_id;
		}

		/**
		 * generate temporary link_id used as array-key
		 *
		 * @param string $app app-name
		 * @param mixed $id
		 * @return string
		 */
		function temp_link_id($app,$id)
		{
			return $app.':'.($app != $this->vfs_appname ? $id : $id['name']);
		}

		/**
		 * returns array of links to $app,$id (reimplemented to deal with not yet created items)
		 *
		 * @param string $app appname
		 * @param string/array $id id of entry in $app or array of links if entry not yet created
		 * @param string $only_app if set return only links from $only_app (eg. only addressbook-entries) or NOT from if $only_app[0]=='!'
		 * @param string $order='link_lastmod DESC' defaults to newest links first
		 * @return array of links or empty array if no matching links found
		 */
		function get_links( $app,$id,$only_app='',$order='link_lastmod DESC' )
		{
			//echo "<p>bolink::get_links(app='$app',id='$id',only_app='$only_app',order='$order')</p>\n";

			if (is_array($id) || !$id)
			{
				$ids = array();
				if (is_array($id))
				{
					if ($not_only = $only_app[0])
					{
						$only_app = substr(1,$only_app);
					}
					end($id);
					while ($link = current($id))
					{
						if (!is_array($link) ||		// check for unlink-marker
						    $only_app && $not_only == ($link['app'] == $only_app))
						{
							continue;
						}
						$ids[$link['link_id']] = $link;
						prev($id);
					}
				}
				return $ids;
			}
			$ids = solink::get_links($app,$id,$only_app,$order);

			if (empty($only_app) || $only_app == $this->vfs_appname ||
			    ($only_app[0] == '!' && $only_app != '!'.$this->vfs_appname))
			{
				if ($vfs_ids = $this->list_attached($app,$id))
				{
					$ids += $vfs_ids;
				}
			}
			//echo "ids=<pre>"; print_r($ids); echo "</pre>\n";

			return $ids;
		}

		/**
		 * Read one link specified by it's link_id or by the two end-points
		 *
		 * If $id is an array (links not yet created) only link_ids are allowed.
		 *
		 * @param int/string $app_link_id > 0 link_id of link or app-name of link
		 * @param string/array $id='' id if $app_link_id is an appname or array with links, if 1. entry not yet created
		 * @param string $app2='' second app
		 * @param string $id2='' id in $app2
		 * @return array with link-data or False
		 */ 
		function get_link($app_link_id,$id='',$app2='',$id2='')
		{
			if (is_array($id))
			{
				if (!strstr($app_link_id,':')) $app_link_id = $this->temp_link_id($app2,$id2);	// create link_id of temporary link, if not given
				
				if (isset($id[$app_link_id]) && is_array($id[$app_link_id]))	// check for unlinked-marker
				{
					return $id[$app_link_id];
				}
				return False;
			}
			if (intval($app_link_id) < 0 || $app_link_id == $this->vfs_appname || $app2 == $this->vfs_appname)
			{
				if (intval($app_link_id) < 0)	// vfs link_id ?
				{
					return $this->fileinfo2link(-$app_link_id);
				}
				if ($app_link_id == $this->vfs_appname)
				{
					return $this->info_attached($app2,$id2,$id);
				}
				return $this->info_attached($app_link_id,$id,$id2);
			}
			return solink::get_link($app_link_id,$id,$app2,$id2);
		}

		/**
		 * Remove link with $link_id or all links matching given $app,$id
		 *
		 * Note: if $link_id != '' and $id is an array: unlink removes links from that array only
		 * 	unlink has to be called with &$id to see the result (depricated) or unlink2 has to be used !!!
		 *
		 * @param $link_id link-id to remove if > 0
		 * @param string $app='' appname of first endpoint
		 * @param string/array $id='' id in $app or array with links, if 1. entry not yet created
		 * @param string $app2='' app of second endpoint
		 * @param string $id2='' id in $app2
		 * @return the number of links deleted
		 */
		function unlink($link_id,$app='',$id='',$owner='',$app2='',$id2='')
		{
			return $this->unlink2($link_id,$app,$id,$owner,$app2,$id2);
		}

		/**
		 * Remove link with $link_id or all links matching given $app,$id
		 *
		 * @param $link_id link-id to remove if > 0
		 * @param string $app='' appname of first endpoint
		 * @param string/array &$id='' id in $app or array with links, if 1. entry not yet created
		 * @param string $app2='' app of second endpoint
		 * @param string $id2='' id in $app2
		 * @return the number of links deleted
		 */
		function unlink2($link_id,$app,&$id,$owner='',$app2='',$id2='')
		{
			if ($this->debug)
			{
				echo "<p>bolink::unlink('$link_id','$app','$id','$owner','$app2','$id2')</p>\n";
			}
			if ($link_id < 0)	// vfs-link?
			{
				return $this->delete_attached(-$link_id);
			}
			elseif ($app == $this->vfs_appname)
			{
				return $this->delete_attached($app2,$id2,$id);
			}
			elseif ($app2 == $this->vfs_appname)
			{
				return $this->delete_attached($app,$id,$id2);
			}
			if (!is_array($id))
			{
				if (!$link_id && !$app2 && !$id2)
				{
					$this->delete_attached($app,$id);	// deleting all attachments
				}
				$deleted =& solink::unlink($link_id,$app,$id,$owner,$app2,$id2);
				
				// only notify on real links, not the one cached for writing or fileattachments
				$this->notify_unlink($deleted);

				return count($deleted);
			}
			if (!$link_id) $link_id = $this->temp_link_id($app2,$id2);	// create link_id of temporary link, if not given

			if (isset($id[$link_id]))
			{
				$id[$link_id] = False;	// set the unlink marker

				if ($this->debug)
				{
					_debug_array($id);
				}
				return True;
			}
			return False;
		}

		/**
		 * get list/array of link-aware apps the user has rights to use
		 *
		 * @param string $must_support capability the apps need to support, eg. 'add', default ''=list all apps
		 * @return array with app => title pairs
		 */
		function app_list($must_support='')
		{
			$apps = array();
			foreach($this->app_register as $app => $reg)
			{
				if ($must_support && !isset($reg[$must_support])) continue;

				if ($GLOBALS['egw_info']['user']['apps'][$app])
				{
					$apps[$app] = $GLOBALS['egw_info']['apps'][$app]['title'];
				}
			}
			return $apps;
		}

		/**
		 * Searches for a $pattern in the entries of $app
		 *
		 * @param string $app app to search
		 * @param string $pattern pattern to search
		 * @return array with $id => $title pairs of matching entries of app
		 */
		function query($app,$pattern)
		{
			if ($app == '' || !is_array($reg = $this->app_register[$app]) || !isset($reg['query']))
			{
				return array();
			}
			$method = $reg['query'];

			if ($this->debug)
			{
				echo "<p>bolink.query('$app','$pattern') => '$method'</p>\n";
			}
			return strchr($method,'.') ? ExecMethod($method,$pattern) : $this->$method($pattern);
		}

		/**
		 * returns the title (short description) of entry $id and $app
		 *
		 * @param string $app appname
		 * @param string $id id in $app 
		 * @param array $link=null link-data for file-attachments
		 * @return string/boolean string with title, null if $id does not exist in $app or false if no perms to view it
		 */
		function title($app,$id,$link=null)
		{
			if ($this->debug)
			{
				echo "<p>bolink::title('$app','$id')</p>\n";
			}
			if (!$id) return '';

			if ($app == $this->vfs_appname)
			{
				if (is_array($id) && $link)
				{
					$link = $id;
					$id = $link['name'];
				}
				if (is_array($link))
				{
					$size = $link['size'];
					if ($size_k = intval($size / 1024))
					{
						if (intval($size_k / 1024))
						{
							$size = sprintf('%3.1dM',doubleval($size_k)/1024.0);
						}
						else
						{
							$size = $size_k.'k';
						}
					}
					$extra = ': '.$link['type'] . ' '.$size;
				}
				return $id.$extra;
			}
			if ($app == '' || !is_array($reg = $this->app_register[$app]) || !isset($reg['title']))
			{
				return array();
			}
			$method = $reg['title'];

			$title = strchr($method,'.') ? ExecMethod($method,$id) : $this->$method($id);

			if ($id && is_null($title))	// $app,$id has been deleted ==> unlink all links to it
			{
				$this->unlink(0,$app,$id);
				return False;
			}
			return $title;
		}

		/**
		 * Add new entry to $app, evtl. already linked to $to_app, $to_id
		 *
		 * @param string $app appname of entry to create
		 * @param string $to_app appname to link the new entry to
		 * @param string $to_id id in $to_app 
		 * @return array/boolean with name-value pairs for link to add-methode of $app or false if add not supported
		 */
		function add($app,$to_app='',$to_id='')
		{
			//echo "<p>bolink::add('$app','$to_app','$to_id') app_register[$app] ="; _debug_array($app_register[$app]);
			if ($app == '' || !is_array($reg = $this->app_register[$app]) || !isset($reg['add']))
			{
				return false;
			}
			$params = $reg['add'];
			
			if ($reg['add_app'] && $to_app && $reg['add_id'] && $to_id)
			{
				$params[$reg['add_app']] = $to_app;
				$params[$reg['add_id']] = $to_id;
			}
			return $params;
		}

		/**
		 * view entry $id of $app
		 *
		 * @param string $app appname
		 * @param string $id id in $app 
		 * @param array $link=null link-data for file-attachments
		 * @return array with name-value pairs for link to view-methode of $app to view $id
		 */
		function view($app,$id,$link=null)
		{
			if ($app == $this->vfs_appname && !empty($id) && is_array($link))
			{
				return $this->get_file($link);
			}
			if ($app == '' || !is_array($reg = $this->app_register[$app]) || !isset($reg['view']) || !isset($reg['view_id']))
			{
				return array();
			}
			$view = $reg['view'];

			$names = explode(':',$reg['view_id']);
			if (count($names) > 1)
			{
				$id = explode(':',$id);
				while (list($n,$name) = each($names))
				{
					$view[$name] = $id[$n];
				}
			}
			else
			{
				$view[$reg['view_id']] = $id;
			}
			return $view;
		}

		/**
		 * Check if $app uses a popup for $action
		 *
		 * @param string $app app-name
		 * @param string $action='view' name of the action, atm. 'view' or 'add'
		 * @return boolean/string false if no popup is used or $app is not registered, otherwise string with the prefered popup size (eg. '640x400)
		 */
		function is_popup($app,$action='view')
		{
			if (!($reg = $this->app_register[$app]) || !$reg[$action.'_popup'])
			{
				return false;
			}
			return $reg[$action.'_popup'];
		}	

		function get_file($link='')
		{
			if (is_array($link))
			{
				return array(
					'menuaction' => 'phpgwapi.bolink.get_file',
					'app' => $link['app2'],
					'id'  => $link['id2'],
					'filename' => $link['id']
				);
			}
			$app = get_var('app','GET');
			$id  = get_var('id','GET');
			$filename = get_var('filename','GET');

			if (empty($app) || empty($id) || empty($filename) || !$this->title($app,$id))
			{
				$GLOBALS['egw_info']['flags']['nonavbar'] = false;
				$GLOBALS['egw']->common->egw_header();
				echo '<h1 style="text-align: center; color: red;">'.lang('Access not permitted')." !!!</h1>\n";
				$GLOBALS['egw']->common->egw_footer();
				$GLOBALS['egw']->common->egw_exit();
			}
			$browser =& CreateObject('phpgwapi.browser');

			$local = $this->attached_local($app,$id,$filename,$_SERVER['REMOTE_ADDR'],$browser->is_windows());

			if ($local)
			{
				Header('Location: ' . $local);
			}
			else
			{
				$info = $this->info_attached($app,$id,$filename);
				$browser->content_header($filename,$info['type']);
				echo $this->read_attached($app,$id,$filename);
			}
			$GLOBALS['egw']->common->egw_exit();
		}

		/**
		 * path to the attached files of $app/$ip or the directory for $app if no $id,$file given
		 *
		 * All link-files are based in the vfs-subdir '/infolog'. For other apps
		 * separate subdirs with name app are created.
		 *
		 * @param string $app appname
		 * @param string $id='' id in $app 
		 * @param string $file='' filename
		 * @param boolean/array $relatives=False return path as array with path in string incl. relatives
		 * @return string/array path or array with path and relatives, depending on $relatives
		 */
		function vfs_path($app,$id='',$file='',$relatives=False)
		{
			$path = $this->vfs_basedir . ($app == '' || $app == 'infolog' ? '' : '/'.$app) .
				($id != '' ? '/' . $id : '') . ($file != '' ? '/' . $file : '');
			
			if ($this->debug)
			{
				echo "<p>bolink::vfs_path('$app','$id','$file') = '$path'</p>\n";
			}
			return $relatives ? array(
				'string' => $path,
				'relatives' => is_array($relatives) ? $relatives : array($relatives)
			) : $path;
		}

		/**
		 * Put a file to the corrosponding place in the VFS and set the attributes
		 *
		 * @param string $app appname to linke the file to
		 * @param string $id id in $app 
		 * @param array $file informations about the file in format of the etemplate file-type
		 * 	$file['name'] name of the file (no directory)
		 * 	$file['type'] mine-type of the file
		 * 	$file['tmp_name'] name of the uploaded file (incl. directory)
		 * 	$file['path'] path of the file on the client computer
		 * 	$file['ip'] of the client (path and ip are only needed if u want a symlink (if possible))
		 * @param string $comment='' comment to add to the link
		 * @return int negative id of phpgw_vfs table as negative link-id's are for vfs attachments
		 */
		function attach_file($app,$id,$file,$comment='')
		{
			if ($this->debug)
			{
				echo "<p>attach_file: app='$app', id='$id', tmp_name='$file[tmp_name]', name='$file[name]', size='$file[size]', type='$file[type]', path='$file[path]', ip='$file[ip]', comment='$comment'</p>\n";
			}
			// create the root for attached files in infolog, if it does not exists
			$vfs_data = array('string'=>$this->vfs_basedir,'relatives'=>array(RELATIVE_ROOT));
			if (!($this->vfs->file_exists($vfs_data)))
			{
				$this->vfs->override_acl = 1;
				$this->vfs->mkdir($vfs_data);
				$this->vfs->override_acl = 0;
			}

			$vfs_data = $this->vfs_path($app,False,False,RELATIVE_ROOT);
			if (!($this->vfs->file_exists($vfs_data)))
			{
				$this->vfs->override_acl = 1;
				$this->vfs->mkdir($vfs_data);
				$this->vfs->override_acl = 0;
			}
			$vfs_data = $this->vfs_path($app,$id,False,RELATIVE_ROOT);
			if (!($this->vfs->file_exists($vfs_data)))
			{
				$this->vfs->override_acl = 1;
				$this->vfs->mkdir($vfs_data);
				$this->vfs->override_acl = 0;
			}
			$fname = $this->vfs_path($app,$id,$file['name']);
			$tfname = '';
			if (!empty($file['path']) && is_array($this->link_pathes) && count($this->link_pathes))
			{
				$file['path'] = str_replace('\\\\','/',$file['path']);	// vfs uses only '/'
				@reset($this->link_pathes);
				while ((list($valid,$trans) = @each($this->link_pathes)) && !$tfname)
				{  // check case-insensitive for WIN etc.
					$check = $valid[0] == '\\' || strstr(':',$valid) ? 'eregi' : 'ereg';
					$valid2 = str_replace('\\','/',$valid);
					//echo "<p>attach_file: ereg('".$this->send_file_ips[$valid]."', '$file[ip]')=".ereg($this->send_file_ips[$valid],$file['ip'])."</p>\n";
					if ($check('^('.$valid2.')(.*)$',$file['path'],$parts) &&
					    ereg($this->send_file_ips[$valid],$file['ip']) &&     // right IP
					    $this->vfs->file_exists(array('string'=>$trans.$parts[2],'relatives'=>array(RELATIVE_NONE|VFS_REAL))))
					{
						$tfname = $trans.$parts[2];
					}
					//echo "<p>attach_file: full_fname='$file[path]', valid2='$valid2', trans='$trans', check=$check, tfname='$tfname', parts=(x,'${parts[1]}','${parts[2]}')</p>\n";
				}
				if ($tfname && !$this->vfs->securitycheck(array('string'=>$tfname)))
				{
					return False; //lang('Invalid filename').': '.$tfname;
				}
			}
			$this->vfs->override_acl = 1;
			$this->vfs->cp(array(
				'symlink' => !!$tfname,		// try a symlink
				'from' => $tfname ? $tfname : $file['tmp_name'],
				'to'   => $fname,
				'relatives' => array(RELATIVE_NONE|VFS_REAL,RELATIVE_ROOT),
			));
			$this->vfs->set_attributes(array(
				'string' => $fname,
				'relatives' => array (RELATIVE_ROOT),
				'attributes' => array (
					'mime_type' => $file['type'],
					'comment' => stripslashes ($comment),
					'app' => $app
			)));
			$this->vfs->override_acl = 0;

			$link = $this->info_attached($app,$id,$file['name']);

			return is_array($link) ? $link['link_id'] : False;
		}

		/**
		 * deletes an attached file
		 *
		 * @param int/string $app > 0: file_id of an attchemnt or $app/$id entry which linked to
		 * @param string $id='' id in app
		 * @param string $fname filename
		 */
		function delete_attached($app,$id='',$fname = '')
		{
			if (intval($app) > 0)	// is file_id
			{
				$link  = $this->fileinfo2link($file_id=$app);
				$app   = $link['app2'];
				$id    = $link['id2'];
				$fname = $link['id'];
			}
			if ($this->debug)
			{
				echo "<p>bolink::delete_attached('$app','$id','$fname') file_id=$file_id</p>\n";
			}
			if (empty($app) || empty($id))
			{
				return False;	// dont delete more than all attachments of an entry
			}
			$vfs_data = $this->vfs_path($app,$id,$fname,RELATIVE_ROOT);
			
			$Ok = false;
			if ($this->vfs->file_exists($vfs_data))
			{
				$this->vfs->override_acl = 1;
				$Ok = $this->vfs->delete($vfs_data);
				$this->vfs->override_acl = 0;
			}
			// if filename given (and now deleted) check if dir is empty and remove it in that case
			if ($fname && !count($this->vfs->ls($vfs_data=$this->vfs_path($app,$id,'',RELATIVE_ROOT))))
			{
				$this->vfs->override_acl = 1;
				$this->vfs->delete($vfs_data);
				$this->vfs->override_acl = 0;
			}
			return $Ok;
		}

		/**
		 * converts the infos vfs has about a file into a link
		 *
		 * @param string $app appname
		 * @param string $id id in app
		 * @param string $filename filename
		 * @return array 'kind' of link-array
		 */
		function info_attached($app,$id,$filename)
		{
			$this->vfs->override_acl = 1;
			$attachments = $this->vfs->ls($this->vfs_path($app,$id,$filename,RELATIVE_NONE));
			$this->vfs->override_acl = 0;

			if (!count($attachments) || !$attachments[0]['name'])
			{
				return False;
			}
			return $this->fileinfo2link($attachments[0]);
		}

		/**
		 * converts a fileinfo (row in the vfs-db-table) in a link
		 *
		 * @param array/int $fileinfo a row from the vfs-db-table (eg. returned by the vfs ls function) or a file_id of that table
		 * @return array a 'kind' of link-array
		 */
		function fileinfo2link($fileinfo)
		{
			if (!is_array($fileinfo))
			{
				$fileinfo = $this->vfs->ls(array('file_id' => $fileinfo));
				list(,$fileinfo) = each($fileinfo);

				if (!is_array($fileinfo))
				{
					return False;
				}
			}
			$lastmod = $fileinfo[!empty($fileinfo['modified']) ? 'modified' : 'created'];
			list($y,$m,$d) = explode('-',$lastmod);
			$lastmod = mktime(0,0,0,$m,$d,$y);

			$dir_parts = array_reverse(explode('/',$fileinfo['directory']));

			return array(
				'app'       => $this->vfs_appname,
				'id'        => $fileinfo['name'],
				'app2'      => $dir_parts[1],
				'id2'       => $dir_parts[0],
				'remark'    => $fileinfo['comment'],
				'owner'     => $fileinfo['owner_id'],
				'link_id'   => -$fileinfo['file_id'],
				'lastmod'   => $lastmod,
				'size'      => $fileinfo['size'],
				'type'      => $fileinfo['mime_type']
			);
		}

		/**
		 * lists all attachments to $app/$id
		 *
		 * @param string $app appname
		 * @param string $id id in app
		 * @return array with link_id => 'kind' of link-array pairs
		 */
		function list_attached($app,$id)
		{
			$this->vfs->override_acl = 1;
			$attachments = $this->vfs->ls($this->vfs_path($app,$id,False,RELATIVE_ROOT));
			$this->vfs->override_acl = 0;

			if (!count($attachments) || !$attachments[0]['name'])
			{
				return False;
			}
			foreach($attachments as $fileinfo)
			{
				$link = $this->fileinfo2link($fileinfo);
				$attached[$link['link_id']] = $link;
			}
			return $attached;
		}

		/**
		 * checks if path starts with a '\\' or has a ':' in it
		 *
		 * @param string $path path to check
		 * @return boolean true if windows path, false otherwise
		 */
		function is_win_path($path)
		{
			return $path[0] == '\\' || strstr($path,':');
		}

		/**
		 * reads the attached file and returns the content
		 *
		 * @param string $app appname
		 * @param string $id id in app
		 * @param string $filename filename
		 * @return string/boolean content of the attached file, null if $id not found, false if no view perms
		 */
		function read_attached($app,$id,$filename)
		{
			$ret = null;
			if (empty($app) || !$id || empty($filename) || !($ret = $this->title($app,$id)))
			{
				return $ret;
			}
			$this->vfs->override_acl = 1;
			$data = $this->vfs->read($this->vfs_path($app,$id,$filename,RELATIVE_ROOT));
			$this->vfs->override_acl = 0;
			return $data;
		}

		/**
		 * Checks if filename should be local availible and if so returns
		 *
		 * @param string $app appname
		 * @param string $id id in app
		 * @param string $filename filename
		 * @param string $id ip-address of user
		 * @param boolean $win_user true if user is on windows, otherwise false
		 * @return string 'file:/path' for HTTP-redirect else return False
		 */
		function attached_local($app,$id,$filename,$ip,$win_user)
		{
			//echo "<p>attached_local(app=$app, id='$id', filename='$filename', ip='$ip', win_user='$win_user', count(send_file_ips)=".count($this->send_file_ips).")</p>\n";

			if (!$id || !$filename || /* !$this->check_access($info_id,EGW_ACL_READ) || */
			    !count($this->send_file_ips))
			{
				return False;
			}
			$link = $this->vfs->ls($this->vfs_path($app,$id,$filename,RELATIVE_ROOT)+array('readlink'=>True));
			$link = @$link[0]['symlink'];

			if ($link && is_array($this->link_pathes))
			{
				reset($this->link_pathes); $fname = '';
				while ((list($valid,$trans) = each($this->link_pathes)) && !$fname)
				{
					if (!$this->is_win_path($valid) == !$win_user && // valid for this OS
					    $win_user &&                                 // only for IE/windows atm
					    eregi('^'.$trans.'(.*)$',$link,$parts)  &&   // right path
					    ereg($this->send_file_ips[$valid],$ip))      // right IP
					{
						$fname = $valid . $parts[1];
						$fname = !$win_user ? str_replace('\\','/',$fname) : str_replace('/','\\',$fname);
						return 'file:'.($win_user ? '//' : '' ).$fname;
					}
					//echo "<p>attached_local: link=$link, valid=$valid, trans='$trans', fname='$fname', parts=(x,'${parts[1]}','${parts[2]}')</p>\n";
				}
			}
			return False;
		}

		/**
		 * reverse function of htmlspecialchars()
		 *
		 * @param string $str string to decode
		 * @return string decoded string
		 */
		function decode_htmlspecialchars($str)
		{
			return str_replace(array('&amp;','&quot;','&lt;','&gt;'),array('&','"','<','>'),$str);
		}

		/**
		 * get title for an event, should be moved to bocalendar.link_title
		 *
		 * @param int/array $event event-id or already read event
		 * @return string/boolean the title (startdate plus subject), of false if event is not found
		 */
		function calendar_title( $event )
		{
			if (!is_object($this->bocal))
			{
				$this->bocal = createobject('calendar.bocalendar');
			}
			if (!is_array($event) && (int) $event > 0)
			{
				$event = $this->bocal->read_entry($event);
			}
			if (!is_array($event))
			{
				return False;
			}
			$format = $GLOBALS['egw_info']['user']['preferences']['common']['dateformat'] . ' '.
				($GLOBALS['egw_info']['user']['preferences']['common']['timeformat'] == '12' ? 'h:i a' : 'H:i');
			
			$name = $GLOBALS['egw']->common->show_date($this->bocal->maketime($event['start']) - $this->bocal->datetime->tz_offset,$format);
			$name .= ': ' . $this->decode_htmlspecialchars($event['title']);	// cal returns entities

			return $name;
		}

		/**
		 * query calendar for an event $matching pattern, should be moved to bocalendar.link_query
		 *
		 * @param string $pattern pattern to search
		 * @return array with id => title pairs of matching events
		 */
		function calendar_query($pattern)
		{
			if (!is_object($this->bocal))
			{
				$this->bocal = createobject('calendar.bocalendar');
			}
			$content = array( );

			if ($event_ids = $this->bocal->search_keywords($pattern))
			{
				foreach($event_ids as $id)
				{
					// only include it in the list, if we have permissions to read it
					if ($this->bocal->check_perms(EGW_ACL_READ,$id))
					{
						$content[$id] = $this->calendar_title( $id );
					}
				}
			}
			return $content;
		}

		/**
		 * get title for an address, should be moved to boaddressbook.link_title
		 *
		 * @param int/array $event address-id or already read address
		 * @return string/boolean the title ([org:] n_familiy[, n_given|n_prefix]), of false if address is not found
		 */
		function addressbook_title( $addr )
		{
			if (!is_object($this->contacts))
			{
				$this->contacts = createobject('phpgwapi.contacts');
			}
			if (!is_array($addr))
			{
				list( $addr ) = $this->contacts->read_single_entry( $addr );
			}
			if (!is_array($addr))
			{
				return False;
			}
			$name = $addr['n_family'];
			if ($addr['n_given'])
			{
				$name .= ', '.$addr['n_given'];
			}
			else
			{
				if ($addr['n_prefix'])
				{
					$name .= ', '.$addr['n_prefix'];
				}
			}
			if ($addr['org_name'])
			{
				$name = $addr['org_name'].($name !== '' ? ': '.$name : '');
			}
			return stripslashes($name);		// addressbook returns quotes with slashes
		}

		/**
		 * query addressbook for $pattern, should be moved to boaddressbook.link_query
		 *
		 * @param string $pattern pattern to search
		 * @return array with id => title pairs of matching addresses
		 */
		function addressbook_query( $pattern )
		{
			if (!is_object($this->contacts))
			{
				$this->contacts = createobject('phpgwapi.contacts');
			}
			$addrs = $this->contacts->read( 0,0,'',$pattern,'','DESC','org_name,n_family,n_given' );
			$content = array( );
			while ($addrs && list( $key,$addr ) = each( $addrs ))
			{
				$content[$addr['id']] = $this->addressbook_title( $addr );
			}
			return $content;
		}

		/**
		 * get title for a project, should be moved to boprojects.link_title
		 *
		 * @param int/array $event project-id or already read project
		 * @return string/boolean the title (number: title), null if project is not found or false if no perms to view it
		 */
		function projects_title( $proj )
		{
			if (!is_object($this->boprojects))
			{
				if (!file_exists(EGW_SERVER_ROOT.'/projects'))	// check if projects installed
				{
					return false;
				}
				$this->boprojects = createobject('projects.boprojects');
			}
			if (!is_array($proj))
			{
				$proj = $this->boprojects->read_single_project( $proj );
			}
			return is_array($proj) ? $proj['number'].': '.$proj['title'] : False;
		}

		/**
		 * query for projects matching $pattern, should be moved to boprojects.link_query
		 *
		 * @param string $pattern pattern to search
		 * @return array with id => title pairs of matching projects
		 */
		function projects_query( $pattern )
		{
			if (!is_object($this->boprojects))
			{
				if (!file_exists(EGW_SERVER_ROOT.'/projects'))	// check if projects installed
					return array();
				$this->boprojects = createobject('projects.boprojects');
			}
			$projs = $this->boprojects->list_projects( array('action'=>'all','query'=>$pattern,'limit'=>FALSE) );
			$content = array();
			while ($projs && list( $key,$proj ) = each( $projs ))
			{
				$content[$proj['project_id']] = $this->projects_title($proj);
			}
			return $content;
		}

		/**
		 * notify other apps about changed content in $app,$id
		 *
		 * @param string $app name of app in which the updated happend
		 * @param string $id id in $app of the updated entry
		 * @param array $data=null updated data of changed entry, as the read-method of the BO-layer would supply it
		 */
		function notify_update($app,$id,$data=null)
		{
			foreach($this->get_links($app,$id,'!'.$this->vfs_appname) as $link_id => $link)
			{
				$this->notify('update',$link['app'],$link['id'],$app,$id,$link_id,$data);
			}
		}

		/**
		 * notify an application about a new or deleted links to own entries or updates in the content of the linked entry
		 *
		 * Please note: not all apps supply update notifications
		 *
		 * @internal 
		 * @param string $type 'link' for new links, 'unlink' for unlinked entries, 'update' of content in linked entries
		 * @param string $notify_app app to notify
		 * @param string $notify_id id in $notify_app
		 * @param string $target_app name of app whos entry changed, linked or deleted
		 * @param string $target_id id in $target_app
		 * @param array $data=null data of entry in app2 (optional)
		 */
		function notify($type,$notify_app,$notify_id,$target_app,$target_id,$link_id,$data=null)
		{
			if ($link_id && isset($this->app_register[$notify_app]) && isset($this->app_register[$notify_app]['notify']))
			{
				ExecMethod($this->app_register[$notify_app]['notify'],array(
					'type'       => $type,
					'id'         => $notify_id,
					'target_app' => $target_app,
					'target_id'  => $target_id,
					'link_id'    => $link_id,
					'data'       => $data,
				));
			}
		}

		/**
		 * notifies about unlinked links
		 *
		 * @internal 
		 * @param array &$links unlinked links from the database
		 */
		function notify_unlink(&$links)
		{
			foreach($links as $link)
			{
				// we notify both sides of the link, as the unlink command NOT clearly knows which side initiated the unlink
				$this->notify('unlink',$link['link_app1'],$link['link_id1'],$link['link_app2'],$link['link_id2'],$link['link_id']);
				$this->notify('unlink',$link['link_app2'],$link['link_id2'],$link['link_app1'],$link['link_id1'],$link['link_id']);
			}	
		}
	}